Voltage regulator



March 24, 1942. c. T. EVANS vbLTAGE REGULATOR Filed July 20, 1959 or. other holding means 3.

bracket l is a second bracket 4.

Patented Mar. 24, 1942 VOLTAGE. REGULATOR Clarence T. Evans, Wauwatosa, Wis., asslgnor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporatlon of Delaware Application July 20, 1939, Serial No. 285,533

coils as will be explained hereinafter. The lever 8 Claims.

This invention relates to voltage regulators and while not limited thereto, is particularly adapted to regulators for illumination control systems, of the distant control type wherein a variable sender voltage is impressed upon a normallybalanced relay which upon response controls the circuit of a lamp regulator to thereby control the illumination intensity of the lamps.

An object of the invention is to provide a system of the aforementioned type which is very sensitive to provide for very closeregulation of the illumination intensity of the lamps.

Another object is to provide a system which is quick in response.

Another object is to provide a system in which a control current flows between the sending and the receiving station only while the lamp voltage departs from the voltage desired as determined by the setting of the sender controller.

Another object is to provide a controller which is positive in opening and closing the circuit of the receiver actuating means.

Another object is to provide a control system in which a voltage which is a function of the operating current of the receiver actuating means is superimposed on the voltage which initiates the operation of the receiver.

Other objects and advantages will hereinafter appear.

The accompanying drawing is illustrative of an embodiment of the invention as applied to an illumination intensity control system.

In the drawing, Fig. 1 is a vertical cross section of a relay forming. a part of the system which embodies the invention.

Fig. 2 is a vertical transverse cross section of the relay along the lines 2-2 of Fig. 1.

Fig. 3 is a diagram of connections of a system embodying the invention.

Referring to Figs. 1 and 2 the relay comprises a bracket I which is arranged to be supported from an insulating base 2 by means of screws Attached to the The bracket [is made of strip metal and comprises a horizontal foot portion 5 by means of which it is fastened to the bracket I, a vertical portion 6 bent upwardly at a right angle to the foot 5, a

horizontal top portion 1 which is parallel to the foot 5 and a depending vertical portion 8 which is in a plane at right angles to the foot 5 and parallel to the portion 6. The portions 6 and '8 are provided with aligned bearings 9 and III to receive a horizontal shaft II for the support of an armature l2. The armature 12 comprises a horizontal lever It to which is attached a bearing bracket 13. At each end the lever H carries a magnetizable core [5, said cores being preferably of U-shape as illustrated. Each of the magnet cores I5 is surrounded by three magnetizing ll is pivoted by bracketv l3 about the pivot shaft II and is rotated thereabout in one direction or another when the pulls upon the two cores l5 differ from each other. The bracket I3 is provided with a depending extension l6 which carries a horizontal pin 11 and a biasing spring I8 is interposed between .the same and the foot portion 5 of bracket 4 so as to bias the armature l2 normally to the central or intermediate position thereof illustrated.

Riveted to the central part of the lever I4. is a double-ended contact spring 19 which carries at each end a contact button 20, which buttons 20 are selectively movable into engagement with adjustable stationary contacts 2'! respectively associated therewith which are screw-mounted on brackets 22, the brackets 22 being supported by the insulating base 2 and each being provided with a terminal-23 for the attachment of circuit wires leading to the stationary contacts.

As shown in Fig. 2 bracket 13 has attached to its extension It, as by spot-welding, one end of a wire or pigtail 39, the other end of which is attached by a screw 40 to the portion 6 of bracket 3. By the means illustrated a good electrical connection is provided between the contact spring l9 and bracket 4; the securing screws ll providing a good electrical connection between brackets l and 4, and a solder-type wiring terminal 42 being clamped in position by one of the screws I to provide for connection of a third wire common to the two circuits (as indicated in Fi 3).

It will thus be apparent that if the armature is rotated in one or the other direction a circuit is closed between a contact button 20 on spring I! and one or the other of the stationary contacts 2!.

Referring now to Fig. 3 the same illustrates a power supply system represented by lines L and U and sender potentiometer 30 having a resistor 30 which is connected between the lines L and L and which is provided with an ad- Justable contact brush 30'. A relay 3| like that Just described is provided with three pairs of magnetizing coils 32, 32 33. 33 and 34, 34', respectively, one coil of each pair surrounding one of the magnet cores [5. The coils 34 and 33' are connected across the lines L and L in such a manner that the pulls which they exert upon the respective cores l5 are equal and tend to rotate the armature l2 in opposite directions thereby tending to balance the latter.

The system further includes a group of lamps 35 and a lamp regulator in the form of a rheostat or transformer 36 the winding of which is connected across the lines L, LP. The lamp regulator 35 is provided with a movable contact brush 36' which connects different taps of the regulator 86 to the bus bar 36". The brush 36' may be moved to different taps by a screw 38 which is operable selectively by a pair of motors 31' and 31 rotatable in opposite directions respectively. A receiver potentiometer rheostat 38 has a resistance 38" which is connected across the lines L and I) and which is provided with a sliding contact brush 38*, which connects the rheostat to the bar 38. The brush 38 is attached to and movable simultaneously with the brush 36 so that the position of the former always corresponds to the illumination intensity of the lamps 35. The pair of coils 32" and 32* on the left and right hand cores respectively of the relay are so connected relatively to each other and to the pair of coils 34 and 34 that a current flowing in one direction or the other in the former pair of coils modifies or counteracts the balanced pull of the latter pair of coils upon the cores l5 whereby the armature l2 and consequently the contact spring is are rotated or tilted in one direction or the other. The coils 32 and 32 are connected in series between the brush 30" and the contact bar 38 Hence if there is a potential difference between the brushes 30 and 38 this is impressed upon the coils 32' and 32 and the resulting current unbalances the relay so that its armature is 1'0- tated in one or the other direction, depending upon whether the lamp intensity and therefore the voltage of potentiometer brush 38" is higher or lower than desired intensity which corresponds to the position of the brush 30 The movable contact buttons 20 of the relay are both connected to line U, while one terminal of each of the operating windings 31 and 31 respectively, of the motors 3F and 31 is connected to line L and the other terminals of the respective windings are connected to the left and right hand stationary terminals 2| respectively of the relay. Hence if the lamp voltage differs from the desired value corresponding to the position of brush 30' the armature I2 is rotated or tilted, and consequently one or the other of the motors 31' or 31* is energized to change the position of lay cores l5 equally but in opposite directions and therefore they do not unbalance the relay. Furthermore the pull is very low because the inductance of the circuit is relatively high. It, however, current flows through one of the motor operating windings, a supplemental voltage is induced in the respective coil 31 or 31 which unbalances the pull exerted by the coils 33 and 33 and substantially increases one of them which assists in maintaining the relay contacts closed until the current in coils 32 and 32 is again substantially zero, at which time the only unbalanced torque remaining is due to the coils 33 and 33*, which is insufficient to maintain the relay contacts closed, whereupon they open and disconnect the respective motor and this again establishes equal current flow in the coils Il and 33 g It is obvious that the coils 31 and 31 need not be arranged in direct inductive relation to the motor windings, but may constitute the secondary windings of current transformers, the primary windings of which are connected in series with the motor operating windings, thus responding to the motor current.

The supplemental voltage may also be impressed by coil 31' or coil 31 upon the circuit between the brushes 3!) and 38 in which case the coils 33 and 33 may be omitted, or the supplemental voltage may be impressed by coil 31' or coil 31 upon the potentiometer rheostat 38 by connecting the coils 31' and/or 31 in series therewith and in parallel with each other.

Furthermore, if it should be desirable to inj crease the naturalsensitivity of the relay, the

' coils 31 and 31 may be connected in the reverse the brush 36' and thus provide the desired lamp brilliancy.

As the system again approaches the balanced condition the current in the coils 32 and 32 approaches zero and the torque exerted by the interaction of the coils 34, 34 and 32, 32 heretofore described also approaches zero, thereby decreasing the pressure of the particular relay contact 2|] against its associated stationary contact 21, thus tending to produce arcing and chattering at said contacts. This is avoided by associating "with each magnet core IS a third coil 33 and 33', respectively, and connecting these coils in parallel with each other across lines L and L in series with coils 31 and 31 respectively; the latter coils being wound in inductive relation to the operating windings 31 and 31 of the motors 31 and 31", respectively. Thus as soon and as long as either motor is energized an additional torque is exerted upon one or the other core I! of the relay to increase the pressure of the active contact button 20 against its associated stationary contact ii to thereby prevent chattering or vibration of the armature and arcing at the contacts. It will be observed that the coils I3 and 33 are permanently connected .across the supply lines in series with the respective coils 31 and 31'. But the current flowing therethrough when both motors are disconnected aflects the pull on the respective reway from that described so that upon energizetion of the respective motor winding 31 or II", the unbalanced pull on the relay armature I! by coils 32 and 32 is decreased or counteracted by the tendency of coil 31' or 31 (as the case may be) to open or disengage the active pair of relay contacts 20, 2|, thus decreasing the range between the closing pull required to be exerted by the coils 32' and 32 and the point at which the pull of said coils for eiiecting closure of one or the other of the sets of contacts 20, 2| is neutralized to permit opening thereof by the balancing elements.

,If desired the lamp circuit and/or the motor circuit energy may be obtained from a source of relatively high alternating voltage, while the con:- trol circuits of lower voltage are conductively insulated therefrom, but in that event both circuits must be operated in synchronism and may for instance be connected by a transformer, which has its primary supplied with energy from the high voltage circuit and whose secondary winding supplies the energy for the low voltage control circuits.

What I claim as new and desire to secure by Letters Patent is:

1. In combination with a controller for varying an operating condition of a circuit, motor means having windings for operating said con-- troller in opposite directions to thereby vary said operating condition, a potentiometer adapted to supply an output voltage varying in accordance with said operating condition, a sender potentiometer adapted to have its output voltage varied selectively, a relay having an energizing winding connected between the output terminals of said potentiometers and adapted to energize said motor windings in accordance with the current flowing in said energizing winding, 9. winding inductively related to said motor winding and means responsiveto the voltages induced in said last named windings to vary the effect'of saidenergizing winding. 2..In combination with a controller for varying an operating condition of a circuit, "motor means having a forward and a reverse winding for operating said controller in opposite-direcaavaeas v ,ing, said-relay being further provided'with two compounding windingseach connected in series tions to thereby vary said operating condition,-

a potentiometer adapted to supply an output voltage varying in accordance with said operat- 7 ing condition, a sender potentiometer adapted to have its output voltage varied selectively, a relay for controlling said motor windings and having an energizing winding connected to have a resultant of the output vdltages of said potentiometers impressed thereon, two windings connected in parallel circuits and each inductively related respectively to one of said motor windings to have induced therein a voltage which is afunction of the motor current, and means responsive to the voltage of said inductively related winding to vary the efi'ectof said energizing winding of said relay.

3, In combination with a controller for varying an operating condition of a circuit, motor means having a forward and a reverse winding for operating said controller in opposite directions to thereby varysaid operating. condition,

a receiver potentiometer adapted to supply an output voltage varying in accordance with said operating condition, a sender potentiometer adapted to have its output voltage varied selectively, a relay having an energizing winding connected between the output terminals of said potentiometers andadapted to energize said mo.- tor windings in accordance with 'the current ilowing in said energizing winding, said relay being further provided with two compounding windings, normally neutralizing each other, and a winding in series with each compounding wind ing. one each of said series windings being inthe current flowing in said relay'ener'giz'ing wind with, one of 'said secondary windings, and responsive to the voltages of said secondary wind:

ings to varythe effect of said relay energizing winding.

'6. In combination with a controller for varying anoperating condition of a circuit, a forward and a reverse motor for selectively operating said controller, each motor having an ener-f gizing'windin'g and 'an inductively related sec-- ductively related to one of said motor windings.

4. In combination with a'controller for varying an operating condition of a circuit, a forward and a reverse motor for selectively operating said controller, each motor having an energizing winding. a secondary winding for each motor arranged to haveindu'ced therein a voltage which is a function of the-motor current, a receiver. potentiometer operable by said motors and adapted to supply an output voltage varying in accordance with said operating condition, a

' sender potentiometer adapted to have its output voltage varied selectively, a-relay having-an energizing winding connected between the output terminals of said potentiometers and adapted to energize said motor windings selectively.. and

, means responsive to the voltages of said secondary windings to vary the eifect. of said energizing winding ofsaid relay.

5. In combination with a controller for varying an operating condition of a circuit, a forward and a reverse motor for selectively operating said controller, each motor having an energizing winding and an inductively related secondary winding, a receiver potentiometer adapted to supply an output voltage varying in accordance with'said operating condition, a sender potentiometer adapted to have its output voltage varied selectively, a relay having an energizing winding connected between the output terminals ondary winding, a receiver potentiometer adapt- .ed to supply'an output voltage varying in accordance with said operating condition, a sender potentiometer adapted to have its output volt- 'age varied selectively, a relay having an auxiliary winding forbalancing same to a center position and adapted .to energize said motor; windings selectively upon its departure from the balanced condition, said relay being further provided with an energizing winding, connected between the output terminals of said. potentiometers and adapted to unbalance said relay in response to the current flowing in said last named winding, and two compounding windings for said relay, each connected in series with one ofthe respective secondary windings and responsive to the. voltages of said secondary windings to vary the Y effect of said relay energizing winding.

'7. A system for controlling the intensity of illumination of a lamp circuit comprising, a voltage regulator adapted to supply a variable volt: age to a lamp circuit, a' drive including motor mean having windings i'or actuating a voltage varying element of said regulator in' opposite directions to thereby vary the .output voltage thereof, a receiver potentiometer operatively connected to said drive to have its output voltage varied in accordance with the output voltage of said voltage regulator, a sender potentiometer adapted to have its output voltage varied selectively, a relay having an energizing winding connected to respond to a resultant of the output voltages oi'Ysaid potentiometers and adapted to 1 energize said motor windings in accordance with v ,the current flowing in said energizing winding,

a winding inductively related to certain of said motor windings, and means responsive to the voltages induced in said inductively related windings to vary the effect of said energizing winding. r

.8. A system'for, controlling the intensity of illumination oi a lamp circuit, comprising, a

voltage regulator adapted to supply a variable voltageto a lamp circuit, a drive including aforward and. a reverse motor for actuating a voltage varying element of said regulator in upposite directions to thereby vary the output volt.- age thereof, a receiver-potentiometer'operatively connected to said drive to have its output voltage varied in accordance with the output voltage of said voltage regulator, a sender poten-.. tiometer adapted to have its output voltage varied selectively, a relay having an energizing winding connected to respond to a resultant of the-output voltages of said potentiometers and of said potentiometers and adapted to energize said motor windings selectively in response to adapted to energize said motors selectively in accordance with the current flowing in said energizing winding, a winding inductively related to an operating winding of each motor, andmeansj to impress the voltage induced in said last named windings upon said energizing winding.

CLARENCE T. EVANS. 

